https://github.com/oboard/moonbit-eval

MoonBit language interpreter
https://github.com/oboard/moonbit-eval

moonbit

Last synced: 5 months ago
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MoonBit language interpreter

• Host: GitHub
• URL: https://github.com/oboard/moonbit-eval
• Owner: oboard
• License: apache-2.0
• Created: 2024-10-16T18:10:36.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2026-01-18T16:58:11.000Z (5 months ago)
• Last Synced: 2026-01-19T00:46:38.858Z (5 months ago)
• Topics: moonbit
• Language: MoonBit
• Homepage: https://mooncakes.io/docs/oboard/moonbit-eval
• Size: 3.14 MB
• Stars: 11
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# MoonBit Eval

[![Version](https://img.shields.io/badge/dynamic/json?url=https%3A//mooncakes.io/assets/oboard/moonbit-eval/resource.json&query=%24.meta_info.version&label=mooncakes&color=yellow)](https://mooncakes.io/docs/oboard/moonbit-eval)

[![GitHub Workflow Status (with event)](https://img.shields.io/github/actions/workflow/status/oboard/moonbit-eval/check.yaml)](https://github.com/oboard/moonbit-eval/actions/workflows/check.yaml)

[![License](https://img.shields.io/github/license/oboard/moonbit-eval)](https://github.com/oboard/moonbit-eval/blob/main/LICENSE)

## Demo

🚀 **[REPL Demo](https://github.com/oboard/moonbit-repl/releases/)**

🚀 **[Notebook Demo https://moonbit-notebook.oboard.fun/](https://moonbit-notebook.oboard.fun/)**

## Introduction

MoonBit Eval is an interpreter for the MoonBit language.

Built on top of the [@moonbitlang/parser](https://github.com/moonbitlang/parser) library, it provides comprehensive and accurate MoonBit syntax support, capable of correctly parsing and executing complex MoonBit code structures including functions, structs, lambdas, loops, and more.

## Quick Start

```moonbit

let vm = MoonBitVM::new()

// Basic expressions

inspect(vm.eval("1 + 2 * 3"), content="7")

inspect(vm.eval("\"hello\" + \" world\""), content="hello world")

// Variables and functions

inspect(vm.eval("let x = 42"), content="()")

inspect(vm.eval("fn double(n: Int) -> Int { n * 2 }"), content="(n: Int) -> Int")

inspect(vm.eval("double(x)"), content="84")

// Control flow

inspect(vm.eval("if x > 40 { \"big\" } else { \"small\" }"), content="big")

// Pattern matching

inspect(vm.eval("match (1, 2) { (a, b) => a + b }"), content="3")

```

## ✨ Features

- ✅ **🥮 Mooncakes Loader**: Load Mooncakes packages at runtime

- ✅ **Builtin FileSystem Library**: Provides basic file system operations.

- ✅ **Eval Function**: Allows dynamic evaluation of MoonBit code strings.

## MoonBit Language Support

| Feature | Status | Description |

|---------|--------|-------------|

| **Core Language** | | |

| Basic Types (Int, Bool, String, Double, Char) | ✅ | Full support for primitive types |

| Expressions (arithmetic, logical, comparison) | ✅ | Complete expression evaluation |

| Variables (let, let mut) | ✅ | Immutable and mutable variables |

| Assignment | ✅ | Variable reassignment and shadowing |

| Multiline strings | ✅ | #\|syntax for multiline string literals |

| String interpolation | ✅ | \{variable} syntax in string literals |

| Type constraints | ✅ | (value : Type) syntax for explicit typing |

| **Control Flow** | | |

| If-else | ✅ | Conditional expressions |

| For loops | ✅ | C-style for loops with continue/break |

| While loops | ✅ | While loop constructs with else clause |

| Loop control | ✅ | Continue and break statements |

| Guard expressions | ✅ | guard condition else { action } syntax |

| Is expressions | ✅ | Pattern matching with 'is' operator |

| Defer expressions | ✅ | defer statement for cleanup code |

| Return expressions | ✅ | Early return from functions |

| Raise expressions | ✅ | Exception throwing with raise |

| Try-catch expressions | ✅ | Exception handling with try-catch |

| Loop expressions | ✅ | loop pattern matching with break/continue |

| **Functions** | | |

| Function definitions | ✅ | Named functions with parameters |

| Named parameters | ✅ | Named and optional parameters |

| Lambda expressions | ✅ | Anonymous functions (x => x * 2) |

| Closures | ✅ | Proper closure environment capture |

| Recursive functions | ✅ | Self-referencing function calls |

| Currying | ✅ | Higher-order function composition |

| External functions | ✅ | Integration with external calls |

| Embedded functions | ✅ | Native function integration |

| **Data Structures** | | |

| Arrays | ✅ | Array creation, indexing, assignment |

| Array methods | ✅ | length, get, push, pop, contains, slice, concat, join |

| Array boolean methods | ✅ | any, all operations |

| Array spread syntax | ✅ | [..array1, ..array2] syntax |

| Array slice operations | ✅ | arr[start:end], arr[start:], arr[:end] syntax |

| Array augmented assignment | ✅ | arr[i] += value, arr[i] *= value syntax |

| Tuples | ✅ | Tuple creation, access, destructuring |

| Structs | ✅ | Custom data types with methods |

| Mutable struct fields | ✅ | Field mutation support |

| Nested struct references | ✅ | Reference semantics for nested structures |

| Record update syntax | ✅ | { ..record, field: new_value } syntax |

| Map literals | ✅ | { "key": value } syntax for map creation |

| **Pattern Matching** | | |

| Basic patterns | ✅ | Constants, variables, wildcards |

| Tuple patterns | ✅ | Destructuring tuples |

| Array patterns | ✅ | Array destructuring |

| Record patterns | ✅ | Struct field matching |

| Range patterns | ✅ | Range expressions (_.. operator for function chaining |

| Function aliases | ✅ | Alias support (e.g., not for %bool_not) |

| Cross-package method calls | ✅ | Method calls across different packages |

| Error handling | ✅ | Result type error handling |

| Group expressions | ✅ | Parenthesized expressions for precedence |

| For-in loops | ✅ | Iterator-based loops |

| Iterator methods | ✅ | iter, map, filter, reduce, for_each |

| Nested iteration | ✅ | Complex nested loop structures |

| Iterator control flow | ✅ | break/continue in iterator contexts |

| **Package System** | | |

| Module imports | ✅ | @package.function syntax |

| Cross-package types | ✅ | Using types from other packages |

| Built-in packages | ✅ | @int, @math, @bigint, @cmp, @list support |

| Package method calling | ✅ | Method calls across package boundaries |

| **IO and FFI** | | |

| Print functions | ✅ | println and print support |

| Embedded functions | ✅ | Native function integration via FFI |

| External function binding | ✅ | Custom function registration |

| **Sorting and Collections** | | |

| List sorting | ✅ | Built-in sort methods for collections |

| Array sorting | ✅ | Sorting operations on arrays |

| Collection methods | ✅ | Comprehensive collection manipulation |

| **Comparison Operations** | | |

| Equality operators | ✅ | == and != operators |

| Relational operators | ✅ | <, >, <=, >= operators |

| Type-aware comparison | ✅ | Proper type checking in comparisons |

| **Constructor Patterns** | | |

| Single argument matching | ✅ | Constructor pattern with single args |

| Named field matching | ✅ | Constructor patterns with named fields |

| Wildcard patterns | ✅ | _ patterns in constructor matching |

| **Functional Programming** | | |

| Higher-order functions | ✅ | Functions as first-class values |

| Function composition | ✅ | Combining functions effectively |

| Closure environments | ✅ | Proper variable capture in closures |

| **Literal Overloading** | | |

| Numeric literal overloading | ✅ | Automatic conversion between numeric types |

| Character literal overloading | ✅ | Char to Int conversion in pattern matching |

| String literal overloading | ✅ | String to Bytes conversion |

| Array literal overloading | ✅ | Array to various types (Bytes, String) conversion |

| Double literal overloading | ✅ | Double to Float precision conversion |

| Map literal overloading | ✅ | Map to Json object conversion |

| Complex overloading scenarios | ✅ | Multi-step type conversions |

| Traits | 🟡 | Interface definitions |

| Trait as expressions | 🟡 | (value as Trait) syntax for trait casting |

| Packages | 🟡 | Module system with @package.function syntax (no trait, trait derive, operator overloading) |

| **Attribute** | | |

| #alias | ✅ | Function alias |

| #external | ❌ | External function binding |

| #callsite | ❌ | Call site information |

| #skip | ❌ | Skipping compilation of a function |

| #cfg | ❌ | Conditional compilation based on configuration |

| **Not Yet Supported** | | |

| Async/await | ❌ | Asynchronous programming |

## Contributing

We welcome contributions to the MoonBit Eval project! Whether it's bug fixes, feature additions, or documentation improvements, your contributions are valuable.

## Community

Join our community for discussions and support:

- QQ Group: **949886784**

![QQ 群](qrcode.jpg)